"The line between hero and villain is often thinner than we think."

The concept of NP-completeness has provided a powerful tool for understanding the complexity of problems.

写作是一种思考的方式，一种理解世界的方式。

The test of our progress is not whether we add more to the abundance of those who have much; it is whether we provide enough for those who have too little.

一般人的毛病，就是容易受局部的蒙蔽，因而不能明白大道理。眼光不妨放长远一些，站得高一些，能看得更广，格局更大。